Remove query level scorer capablity

[epugh]

Is your feature request related to a problem? Please describe.
A somewhat hidden feature is that you can set a scorer at the query level, that is used instead of the case level scorer!

This turns out, according to @softwaredoug, to come from the origin of Quepid.. Back before we added classical relevance metrics to Quepid, it was used more as an individaul query tool, and only later were queries grouped into cases.

Describe the solution you'd like
Rip out this capablity, because what is a AP@10 for one query when you are using NDCG@10 for the whole case mean?

Describe alternatives you've considered
While not exactly an alternative, we are keeping the adhoc scorer for now that lets you write unit tests in Quepid. Sure, you could do it in Python etc, but what if you want to pair with your content curator using Quepid?

Additional context
This will simplify our codebase in Angular1.

[epugh]

This has been completed in PR #100

[epugh]

Closed now that #100 is merged.